This invention relates to a method and apparatus for magnetically recording running condition of a vehicle.
A conventional system of this kind comprises a magnetic disc rotated in proportion to a vehicle speed and a magnetic head through which pulse signals of a constant frequency are applied, whereby a vehicle speed is recorded. The conventional recording system described above is, however, disadvantageous in that only one turn of the magnetic disc is available to the recording and that the recording time varies with a vehicle speed.
Another conventional one utilizes a magnetic tape instead of a magnetic disc to which a vehicle speed is recorded. However, the recording time of the magnetic tape is at the most one or two hours, which, otherwise, require complicated speed reducing means to record the vehicle speed all day long.